Double-row tapered roller bearing unit

Abstract

A double-row tapered roller bearing unit, comprising an outer ring, an inner ring and a retainer arranged on both sides of the inner ring in the axial direction, wherein a raceway for the tapered roller is arranged between the outer ring and the inner ring, a sealing element is arranged between the retainer and the outer ring, the sealing element is in interference fit with the outer ring at one end in the radial direction, the sealing element is in clearance fit with the retainer, and a labyrinth is formed between the sealing element and the retainer. The utility model has the advantages that the sealing element is in interference fit with the outer ring and in clearance labyrinth fit with the retainer, so that the combination of contact type fixation and non-contact type labyrinth protection is realized. The interference fit of the outer ring makes the positioning of the sealing element reliable, and the sealing element will not slide and rub with the retainer, so that the large amount of heat caused by the continuous rubbing of the traditional contact type lip is fundamentally eliminated, the temperature rise of the bearing is effectively inhibited, the oxidation of the lubricating grease is delayed, and the maintenance-free period is prolonged.

Description

Technical Field

[0001] This utility model relates to a transmission device, and more particularly to a double-row tapered roller bearing unit. Background Technology

[0002] In the wheelset axle boxes of railway train bogies, double-row tapered roller bearing units are widely used as core load-bearing components, bearing the radial forces generated by the vehicle's own weight and loads, as well as the axial forces generated when traversing curves or encountering lateral disturbances. These bearing units are typically assembled in a preloaded state, with the inner ring interference-fitted to the axle and the outer ring installed inside the axle box. During train operation, the two rows of tapered rollers roll between the inner and outer ring raceways, relying on grease for friction reduction and heat dissipation. Sealing devices are installed at both ends to prevent external sand, dust, and moisture intrusion and to prevent grease leakage, thereby maintaining stable bearing operation and reliable service life under long-distance, high-speed, and variable track conditions.

[0003] Existing double-row tapered roller bearing units for railway trains are ill-suited to the increasingly stringent requirements for maintenance-free and long-life operation. When using contact-type rubber lip seals, the continuous friction between the lower lip and rotating components during high-speed operation generates significant heat, causing a substantial temperature rise in the bearing and accelerating grease oxidation and deterioration, thus failing to guarantee long-term maintenance-free operation. While non-contact labyrinth seals can mitigate the temperature rise issue, their tortuous clearances offer limited protection against fine dust and moisture, allowing external contaminants to easily penetrate the bearing. This leads to wear and corrosion of the rolling elements and raceways, significantly shortening the bearing's actual service life and increasing maintenance costs and risks. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a double-row tapered roller bearing unit that balances low frictional temperature rise with high pollution protection performance.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a double-row tapered roller bearing unit, comprising an outer ring and an inner ring, with retaining rings respectively disposed on both axial sides of the inner ring. A raceway for inserting tapered rollers is provided between the outer ring and the inner ring. A sealing element is provided between the retaining ring and the outer ring. One radial end of the sealing element forms an interference fit with the outer ring, and a clearance fit is formed between the sealing element and the retaining ring. A labyrinth channel is formed between the sealing element and the retaining ring.

[0006] The beneficial effects of this invention are as follows: by setting the seal and outer ring to an interference fit and the seal and retaining ring to a clearance labyrinth fit, a combination of contact fixing and non-contact labyrinth protection is achieved. The interference fit at the outer ring ensures reliable positioning of the seal and prevents sliding friction as the retaining ring rotates, fundamentally eliminating the large amount of heat generated by continuous friction in traditional contact lip seals, effectively suppressing bearing temperature rise, delaying grease oxidation, and thus extending the maintenance-free period. The labyrinth channel on the retaining ring side forms a tortuous barrier against dust, sand, and moisture in a non-contact manner, improving intrusion prevention capabilities without additional frictional heat. As a preferred embodiment, the seal can be made by stamping a metal sheet, with an annular fixing wall extending radially from its outer edge. This fixing wall is pressed into a pre-set stepped annular groove at the end of the outer ring, forming a strong radial interference fit and providing stable axial and radial support for the seal as a whole. As another preferred approach, the seal can be designed as a bowl-shaped structure that protrudes outwards as a whole. The protruding part expands the grease filling cavities on both sides of the bearing, increases the amount of grease stored, and at the same time increases the contact area with the outside air, enhancing heat dissipation and further improving the thermal balance of the bearing in high-speed and heavy-load applications.

[0007] Furthermore, both the inner ring and the retaining ring are connected to the rotating shaft and are driven to rotate by the rotating shaft. The sealing element includes a labyrinth section with an E-shaped cross-section. The portion of the retaining ring corresponding to the labyrinth section also has an E-shaped cross-section. The two intersect to form a labyrinth path.

[0008] The labyrinth section and the retaining ring are both designed with E-shaped mating sections that intersect each other, creating multiple folds in the gap path between them. This significantly increases the flow resistance and stroke length for external contaminants, constructing multiple barriers within a limited radial space. During rotation, the E-shaped groove on the retaining ring does not contact the E-shaped teeth on the stationary seal, preventing frictional heat generation. However, the centrifugal effect and tortuous channels effectively inhibit moisture and dust from entering the bearing. As a preferred embodiment, the labyrinth section of the seal may have a first, second, and third ring tooth arranged radially inward. The retaining ring has corresponding outer and inner ring grooves. The first ring tooth extends into the outer ring groove, and the third ring tooth extends into the inner ring groove, with the three interlocking to form at least four folds in the labyrinth path. Alternatively, a radially extending dustproof thin edge can be provided on the outermost ring tooth end face of the seal. This thin edge maintains a very small, uniform gap with the outer surface of the retaining ring to form a pre-filter, initially removing large-diameter particles.

[0009] Furthermore, the gap between the seal and the retaining ring is 0.45-0.55 mm.

[0010] A 0.45-0.55mm gap between the seal and the retaining ring provides ample running space for the retaining ring to rotate with the shaft, preventing contact friction due to thermal expansion or slight vibration, while also controlling the throttling gap within a narrow range. This narrow gap creates a micro-throttling orifice effect in the labyrinth channel. When external fluid or dust-laden airflow attempts to pass through, its pressure is dissipated step by step, reducing the flow velocity and making it difficult for impurities to enter the next labyrinth cavity. As a preferred method, micro-protrusions evenly distributed around the root of the labyrinth ring teeth of the seal can be provided. These protrusions automatically center with the corresponding ring grooves on the retaining ring during assembly, ensuring that the gap difference along the circumference is less than the machining tolerance and avoiding local gap enlargement caused by misalignment. As another preferred method, the opposite end faces of the seal and the retaining ring can be machined with guide bevels. During installation, axial engagement allows for easy alignment of the parts, naturally forming a uniform gap band without adjustment, facilitating rapid assembly on the production line.

[0011] Furthermore, the outer ring includes a contact sealing groove, and the sealing element includes a contact sealing part corresponding to the contact sealing groove, wherein the contact sealing groove and the contact sealing part cooperate to achieve contact sealing.

[0012] By adding a contact sealing groove to the outer ring and engaging with the contact sealing part of the seal, an additional radial contact seal is added to the bearing inside the labyrinth channel, forming a combined protection system of "outer labyrinth, inner contact". Large external particles and splashing water are first intercepted and slowed down by the labyrinth channel, while residual fine moisture and dust are then blocked by the contact sealing part, significantly reducing the amount of contaminants entering the raceway area. As a preferred embodiment, the contact sealing part can be a rubber ring integrally vulcanized with the metal seal body, with at least one annular sealing lip on the outer circumference of the rubber ring. After installation, this sealing lip forms elastic radial compression within the contact sealing groove, blocking media penetration through constant contact pressure. As another preferred embodiment, the contact sealing groove can be provided with a wavy or sawtooth circumferential contour. When the surface of the contact sealing part is pressed, it embeds into the recesses of this contour, forming multiple micro-contact barriers. Even if grease leaks slightly under the action of centrifugal force, it can be captured in each valley and replenished to the sealing interface.

[0013] Furthermore, the contact sealing groove includes an abutting wall and an interference groove that abut against the axial end face of the contact sealing part, and the contact sealing part is provided with a protrusion that cooperates with the interference groove.

[0014] The abutment wall provides a clear axial assembly reference for the seal, preventing axial movement of the seal under stress and ensuring long-term stability of the relative position of the labyrinth clearance and the contact seal. The fit between the interference groove and the protrusion achieves a firm yet flexible contact seal through radial interference. Compared to simple radial clamping, this groove-protrusion structure can accommodate slight axial misalignment between the outer ring and the retaining ring. As a preferred option, the interference groove can be machined into a trapezoidal annular groove, and the protrusion can be formed into a matching trapezoidal annular rib. During pressing, the inclined surfaces on both sides of the annular rib gradually wedge, reducing assembly thrust and maintaining stable contact stress during bearing operation, thus preventing plastic creep. As another preferred option, an axially extending annular rib can be added to the abutment wall, and a corresponding annular groove can be provided on the axial end face of the contact seal. When the two are interlocked, they form an end face labyrinth, which can effectively block external media even when there is micron-level vibration displacement on the axial mating surface.

[0015] Furthermore, the contact sealing part is also provided with a deformation groove, one end of which is connected to one end of the protrusion, and the outer diameter of the deformation groove is smaller than the outer diameter of other parts of the radial end face of the contact sealing part that contacts the contact sealing groove.

[0016] The design of the deformation groove provides a clear stress relief zone for the protrusion during interference fit installation. By locally varying the cross-section, the bending stiffness at the root of the protrusion is reduced, facilitating radial compression deformation. This ensures sufficient interference seal pressure while preventing excessive installation resistance or tearing of the sealing material. Thermal expansion and contraction due to temperature changes during operation can also be buffered by the deformation groove, maintaining stable sealing contact force. As a preferred embodiment, the deformation groove can be an annular groove cut into the inner root of the contact seal. The radial depth of the groove is greater than the radial extension height of the protrusion, allowing the protrusion to swing inward as a whole under pressure, and the continuous arc at the bottom of the groove prevents stress concentration. Another preferred embodiment is to embed a ring-shaped metal frame within the deformation groove. The frame has an outwardly open U-shape cross-section. After the protrusion is pressed into the interference groove, the two arms of the metal frame elastically open, providing additional rebound force. Even after long-term static placement or operation, the sealing force does not significantly decrease, thus maintaining its protective capability over a long period. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of an embodiment of the present utility model; Figure 2 This is a partial cross-sectional view of the labyrinthine connection between the seal and the retaining ring in an embodiment of this utility model. Figure 3 This is a partial cross-sectional view of the sealing area where the seal contacts the outer ring in an embodiment of this utility model; Figure 4 This is a cross-sectional view of the sealing element according to an embodiment of the present invention; Figure 5This is a partial cross-sectional view of the contact sealing groove in an embodiment of the present invention. Detailed Implementation

[0018] This utility model embodiment provides a double-row tapered roller bearing unit, such as... Figure 1-5 As shown: This bearing unit includes an outer ring 1, an inner ring 2, and retaining rings 3 located on both axial sides of the inner ring 2. A raceway is formed between the outer ring 1 and the inner ring 2, and tapered rollers 5 are fitted within the raceway. The inner ring 2 and the two retaining rings 3 are all connected to a rotating shaft (not shown in the figure) and are driven to rotate synchronously by the rotating shaft (not shown in the figure). A seal 4 made of metal material is provided between the retaining rings 3 and the outer ring 1. The retaining ring 3 itself integrates the function of a sealing seat, eliminating the need for a traditional separate sealing seat. The outer ring 1 has contact sealing grooves 11 with stepped grooves at both ends of its outer edge. The radially outward end of the seal 4 forms a contact sealing part 42, which is fixed in the contact sealing groove 11 by an interference fit, achieving reliable fixation of the seal 4 relative to the stationary outer ring 1 and preventing loosening. The radially inward end of the seal 4 is clearance-fitted with the retaining ring 3, forming a labyrinth seal structure. Specifically, the seal 4 has a labyrinth portion 41 extending towards the retaining ring 3, and the cross-section of the labyrinth portion 41 is E-shaped. The retaining ring 3 has a labyrinth mating portion 31 corresponding to the labyrinth portion 41, also with an E-shaped cross-section. The labyrinth portion 41 and the labyrinth mating portion 31 intersect and insert into each other, forming a winding labyrinth path. The gap between them is controlled between 0.45mm and 0.55mm to ensure no collision occurs during rotation. The seal 4 protrudes from the end face of the outer ring 1, increasing the grease injection space and heat dissipation space of the bearing, eliminating contact friction, and providing ventilation.

[0019] A contact sealing structure is also provided between the outer ring 1 and the seal 4. A contact sealing groove 11 is machined on the outer ring 1, and a corresponding contact sealing portion 42 is provided on the seal 4. The two work together to achieve a static contact seal. The contact sealing groove 11 has an axial abutment wall 111 and an interference groove 112. The inner diameter of the interference groove 112 is smaller than the inner diameter of the remaining radial circumferential surface of the contact sealing groove 11 that contacts the contact sealing portion 42. A protrusion 421 is formed on the contact sealing portion 42 corresponding to the interference groove 112, and a deformation groove 422 is formed on the contact sealing portion 42. One end of the deformation groove 422 is connected to one end of the protrusion 421. The outer diameter of the deformation groove 422 is smaller than the outer diameter of the other radial end faces of the contact sealing portion 42 that contact the contact sealing groove 11, so as to provide elastic deformation space during press-fitting and ensure the reliability of the interference fit. Through the interference fit between the contact sealing portion 42 and the contact sealing groove 11, the seal 4 is doubly fixed to the outer ring 1.

[0020] The working principle of this embodiment is as follows: During assembly, the inner ring 2 and tapered rollers 5 are inserted into the raceway of the outer ring 1. Two retaining rings 3 are fixed at both ends of the inner ring 2 and are connected to the rotating shaft (not shown in the figure) for transmission. The seal 4 is pressed into the contact sealing groove 11 of the outer ring 1 through the contact sealing part 42, the protrusion 421 is engaged with the interference groove 112, and the deformation groove 422 is elastically deformed under pressure, so that the contact sealing part 42 and the outer ring 1 are firmly interference-fitted. When the rotating part rotates, the retaining ring 3 rotates synchronously with the rotating shaft (not shown in the figure). The labyrinth part 41 of the seal 4 and the labyrinth mating part 31 on the retaining ring 3 always maintain a gap of 0.45mm-0.55mm, forming a non-contact labyrinth seal, which can effectively prevent grease leakage, allow internal gas exchange, and has no friction loss. The design of the protruding end face of the seal also provides sufficient space for grease injection and heat dissipation. The overall structure is simple, easy to manufacture, and has reliable sealing.

[0021] The above embodiments are merely one preferred embodiment of the present utility model. Ordinary changes and substitutions made by those skilled in the art within the scope of the present utility model's technical solution are all included within the protection scope of the present utility model.

Claims

1. A double-row tapered roller bearing unit, comprising an outer ring and inner rings respectively disposed on opposite axial sides of the inner ring, a raceway for inserting tapered rollers being provided between the outer ring and the inner ring, and a sealing element being provided between the retaining rings and the outer ring, characterized in that: The seal has an interference fit with the outer ring at one radial end, a clearance fit with the retaining ring, and a labyrinthine channel between the seal and the retaining ring.

2. The double-row tapered roller bearing unit according to claim 1, characterized in that: Both the inner ring and the retaining ring are connected to the rotating shaft and are driven to rotate by the rotating shaft. The sealing element includes a labyrinth section with an E-shaped cross-section. The portion of the retaining ring corresponding to the labyrinth section also has an E-shaped cross-section. The two intersect to form a labyrinth path.

3. The double-row tapered roller bearing unit according to claim 2, characterized in that: The gap between the seal and the retaining ring is 0.45-0.55 mm.

4. The double-row tapered roller bearing unit according to claim 1, characterized in that: The outer ring includes a contact sealing groove, and the sealing element includes a contact sealing part provided corresponding to the contact sealing groove. The contact sealing groove and the contact sealing part cooperate to achieve contact sealing.

5. The double-row tapered roller bearing unit according to claim 4, characterized in that: The contact sealing groove includes an abutting wall and an interference groove that abut against the axial end face of the contact sealing part, and the contact sealing part is provided with a protrusion that cooperates with the interference groove.

6. The double-row tapered roller bearing unit according to claim 5, characterized in that: The contact sealing part is also provided with a deformation groove, one end of which is connected to one end of the protrusion. The outer diameter of the deformation groove is smaller than the outer diameter of other parts of the radial end face of the contact sealing part that contacts the contact sealing groove.

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